Field
Aspects of the present disclosure generally relate to a shape-memory alloy (SMA) actuator and a cooling device having increased cooling efficiency.
Description of the Related Art
An SMA is an alloy that “remembers” its original shape and that when deformed returns to its pre-deformed shape when heated. Actuation of the SMA can be effected through heating and cooling of the SMA. In one example, an SMA actuator may include a torque tube that rotates in a first direction when the torque tube is heated, and rotates in a second direction when the torque tube cools. The rate of heating and cooling (measured in degrees of rotation per second) controls the rate of movement of the SMA actuator. The rate of heating can be controlled by controlling a heater, and the rate of cooling may depend on ambient conditions or a fluid flow.
Conventional SMA actuators are capable of being rapidly heated, however, satisfactory cooling times have posed challenges. The unsatisfactory cooling times have limited the cycle and/or response time of the SMA actuator. Additionally, cooling rates may be insufficient when the actuator is responsible for moving heavy or large components. More specifically, the torque tube will include a higher thermal mass due to an increased size necessary to provide more torque to rotate the larger component. The higher thermal mass of the SMA cannot be cooled at a fast enough rate to move the larger component at desired speeds.
Therefore, there is a need for an SMA actuator with increased cooling rates.